DESCRIPTION: The objective of this application involves the development of a noninvasive measurement of total hemoglobin/hematocrit. The applicant has developed proprietary technology specifically designed for noninvasive chemical analysis by near-infrared photometry. One aspect of this technology is the development of the methods to minimize the impact of radiation scattering by blood and tissue components. It is anticipated that for noninvasive measurement of total hemoglobin/ hematocrit, where analyte absorption coefficients are relatively high in comparison with scattering coefficients, the use of specialized, proprietary optical configurations will minimize the effect of scattering and is likely to provide more accurate measurements than previously realized. The applicants propose to measure and optimize device precision as a function of the optical parameters in these configurations for a device operating on human subjects at wavelengths that should be suitable for a total hemoglobin measurement.